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Prospects of borehole NMR instruments and applications Dedicated to Professor Chaohui Ye on the occasion of his 80th birthday

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Magnetic Resonance Letters 2022年第4期2卷 224-232页

作者： Sihui Luo jiangfeng guo Lizhi Xiao College of Artificial Intelligence and College of Petroleum Engineering China University of PetroleumBeijing102249China State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China

Borehole nuclear magnetic resonance(NMR)is a powerful technology to characterize the petrophysical properties of underground reservoirs in the petroleum *** rising complexity of oil and gas exploration and development objectives,as well as the novel application contexts of underground reservoirs,have led to increasingly demanding requirements on borehole NMR technology including instrument design and related processing *** mini review summarizes the advances and applications of borehole NMR instruments along with some future *** may be helpful for researchers and engineers in the petroleum industry to understand the development status and future trends of borehole NMR technology.

关键词： Borehole Nuclear magnetic resonance(NMR) Instrument Oil and gas exploration and development Prospects

Experimental and Numerical Study of an 80-kW Zigzag Printed Circuit Heat Exchanger for Supercritical CO_(2)Brayton Cycle

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Journal of Thermal Science 2021年第4期30卷 1289-1301页

作者： ZHANG Huzhong CHENG Keyong HUAI Xiulan ZHOU Jingzhi guo jiangfeng Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

In this study,an experimental system was built to investigate the global performance of an 80-k W zigzag printed circuit heat exchanger(PCHE).It could meet the requirement of the pre-cooler for the supercritical carbon dioxide(S-CO_(2))Brayton power cycle and the modified effectiveness considering the pinch point is between 61.5%and 79.3%.When the outlet S-CO_(2)temperature is near the pseudo-critical point,the thermo-physical properties have more effects on heat transfer performance compared to flow *** the local performance,the mass flow rates of both sides have crucial influences on the location where the peak of S-CO_(2)Nusselt number occurs while only the S-CO_(2)flow rate affects the variation of the peak *** addition,the influence of the radius of curvature on the secondary-flow should not be *** the end,new empirical correlations were proposed considering the drastic variations of the Prandtl number.

关键词： Printed Circuit Heat Exchanger(PCHE) supercritical carbon dioxide(S-CO_(2)) pre-cooler zigzag channel thermal-hydraulic performance

The entransy dissipation minimization principle under given heat duty and heat transfer area conditions

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Chinese Science Bulletin 2011年第19期56卷 2071-2076页

作者： guo jiangfeng XU MingTian CHENG Lin Institute of Thermal Science and Technology Shandong University Jinan 250061 China

Under given heat duty and heat transfer area conditions, the equipartition of the entransy dissipation (EoED) principle, the equipartition of the temperature difference (EoTD) principle, and the equipartition of the heat flux (EoHF) principle are applied to the optimization design of a heat exchanger with a variable heat transfer coefficient. The results show that the difference between the results obtained using the EoED and EoTD principles is very small, far smaller than that between the results obtained using the EoED and EoHF principles. The correct entransy dissipation minimization principle is chosen to optimize the parameters in the hot and cold fluids in a two-fluid heat exchanger, under given heat duty and heat transfer area conditions. The results indicate that the proper choice of the two alternative fluids has an important role in the successful application of the entransy dissipation minimization principle. The fluid that could improve the total heat transfer coefficient should be chosen, or the fluid that makes the temperature profiles of the hot and cold fluids parallel and decreases the temperature difference between the hot and cold fluids after optimization simultaneously, could be the proper one.

关键词：换热面积最小化热负荷耗散总传热系数优化设计热流体温度分布

Entransy dissipation minimization for optimization of heat exchanger design

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Chinese Science Bulletin 2011年第20期56卷 2174-2178页

作者： LI XueFang guo jiangfeng XU MingTian CHENG Lin Institute of Thermal Science and Technology Shandong UniversityJinan 250061China

In this paper,by taking the water-water balanced counterflow heat exchanger as an example,the entransy dissipation theory is applied to optimizing the design of heat *** certain conditions,the optimal duct aspect ratio is determined *** the heat transfer area or the duct volume is fixed,analytical expressions of the optimal mass velocity and the minimal entransy dissipation rate are *** results show that to reduce the irreversible dissipation in heat exchangers,the heat exchange area should be enlarged as much as possible,while the mass velocity should be reduced as low as possible.

关键词：耗散理论换热器设计优化最小化低质量流速传热面积热交换器

Principle of equipartition of entransy dissipation for heat exchanger design

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Science China(Technological Sciences) 2010年第5期53卷 1309-1314页

作者： guo jiangfeng,XU MingTian & CHENG Lin Institute of Thermal Science and Technology,Shandong University,Jinan 250061,China Institute of Thermal Science and Technology Shandong University Jinan China

In the present work,a principle of equipartition of entransy dissipation(EoED) for heat exchanger design is established,which says that for a heat exchanger design with given heat duty and heat transfer area,the total entransy dissipation rate reaches the minimum when the local entransy dissipation rate is uniformly distributed along the heat *** the heat transfer coefficient is unfixed,the total entransy dissipation obtained by the EoED principle is less than that obtained by the principle of equipartition of temperature difference(EoTD).Furthermore,the exchanger effectiveness obtained by the EoED principle is larger than that obtained by the EoTD *** the heat transfer coefficient is fixed,the EoED principle is equivalent to the EoTD *** show that the equipartition of entropy production(EoEP) and EoED principles give rise to difference in entropy generation and entransy dissipation for a heat exchanger optimization *** discrepancies are caused by distinct features of entropy production minimization and entransy dissipation minimization principles,the former is to optimize the design of heat exchanger by making the lost available work minimum,while the latter is not involved with heat-work *** is found that the entropy generation number is not suitable for evaluating heat exchanger performance,since it directly depends on the inlet and outlet temperatures of working *** the contrary,the entransy dissipation number is not directly related to the inlet and outlet temperatures of working ***,the entransy dissipation number is more suitable for serving as a criterion to evaluate heat exchanger performance.

关键词： heat exchanger entropy production entropy generation number entransy dissipation entransy dissipation number

Flow and Heat Transfer Features of Supercritical Pressure CO_(2) in Horizontal Flows under Whole-Wall Heating Conditions

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Frontiers in Heat and Mass Transfer 2024年第6期22卷 1575-1595页

作者： jiangfeng guo Hongjie Yu College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing100029China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China Department of Chemical Engineering Imperial College LondonLondonSW72AZUK

Based on the first and second laws of thermodynamics,the heat transfer and flow(thermohydraulic)characteristics of horizontal supercritical pressure CO_(2)(S-CO_(2))in a circular pipe under heating conditions were investigated *** flows in two different diameters(d)of 4 and 6 mm were simulated in pipes with pressures of 8 MPa,mass fluxes(G)of 300 and 400 kg/(m^(2)·s),and heat fluxes(q)of 50,75 and 100 kW/m^(2).In the d=4 mm pipe,the peak heat transfer coefficient(hb)was about 3 times higher than in the d=6 mm pipe,while the entropy production due to fluid friction in the 4 mm pipe was on average 1.1 times higher,and the entropy production due to heat transfer was on average about 67%lower.A 4 mm tube was employed to further evaluate the influence of the applied wall heat flux,the results demonstrated that the irreversibility due to heat transfer was on average more than 4 times higher when heat flux density was 100 kW/m^(2)than when the heat flux density was 50 kW/m^(2),while the peak of heat transfer coefficient increased by 1.4 times as q was decreased from 100 to 50 kW/m^(2).The effect of thermal acceleration was ignored,while the buoyancy effect resulted in secondary flow and significantly affected the flow and heat transfer *** jet flows were found in the vicinity of the lower wall of the pipe,which made the two fields of velocity and temperature gradient more synergistic,leading to an enhancement in heat transfer in the vicinity of the upper *** aggravation of heat transfer resulted in high irreversibility of heat transfer in the cross-sectional area near the wall,while the local friction irreversibility was less affected by the buoyancy effect,and the distribution was *** uneven distribution of thermophysical properties also confirmed that the enhanced heat transfer occurred near the wall area at the bottom of the pipe.

关键词： Effect of buoyancy heat transfer deterioration irreversible loss supercritical pressure CO2(S-CO2) field synergy principle

The release of ^(14)C-chlorsulfuron bound residue by autoclaving method and its identification

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Nuclear Science and Techniques 1999年第2期10卷 105-110页

作者： guo jiangfeng SUN Jinhe PING Xiaofei YE Qingfu(Instiftrte of Nuclear Agricultural Science, Zhejiang University (Huajiachi campus),Key Las. of Nuclear Agricultural Science, the Ministry of Agriculture, Hangzhou 310029, China National Rice Research insti Institute of Nuclear Agricultural Science Zhejiang University (Huajiachi Campus) Ministry of Agriculture Hangzhou 310029 China China National Rice Research Institute Hangzhou 310006 China

When individual microorganisms were used to release bound pesticide residues, it was ussually not take into full account whether the autoclavingmethod could lead to the release of bound residues. The soil containing bound 14Cchlorsulfuron residues was treated with an autoclave in this study. The results revealthat the bound 14C-chlorsulfuron residue can be released from the soil when treatedwith the autoclave and the release rate can be remarkably enhanced by adding water into the soil when subjected to such treatment. A TLC analysis showed that thereleased 14C-residue was one of the degraded products of 14C-chlorsulfuron. Afterderivatization and analysis using the GC-MS, the released 14C-residue was tentativelyidentified aS 2-amino-4-hydroXyl-6-methyl-1,3,

关键词：土壤农药残留量释放

Distribution of ^(14)C-chlorsulfuron bound residues in soil organic matter

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Nuclear Science and Techniques 1999年第3期10卷 171-175页

作者： guo jiangfeng SUN Jinhe YE Qingfu (Institute of Nuclear Agricultural Science, Zhejiang University(Huajiachi campus),Key Laboratory of Nuclear Agricultural Science, the Ministry of Agriculture,Hangzhou 310029) 浙江大学农业与生物技术学院核农学重点开放实验室浙江杭州 310029 浙江大学农业与生物技术学院核农学重点开放实验室浙江杭州

The reason why chlorsulfuron(2-chloro-N-[4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]benzenesulfonamide)bound residues can still make an in-jury to rotational crops is still kept unknown. The experiment was conducted under laboratory conditions to determine the dynamics of extractable and non-extractable (bound) residues of chlorsulfuron in soil, and the distribution of chlorsulfuron bound residues in organic matter fractions. The results showed that extractable 14C-residues decreased t0 25.12% of applied chlorsulfuron over an incubation period of 150 days;this in turn, the formation of bound residues increased to 47.07% of the applied. The proportions of 14C-bound residues in soil organic matter fractions increase in order of: humic acid (HA)

关键词：土壤有机质灰黄霉酸腐殖酸

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气凝胶复合材料中遮光剂及纤维的掺杂方法

科学通报 2017年第21期62卷 2442-2450页

作者：郭江峰赵越唐桂华西安交通大学能源与动力工程学院热流科学与工程教育部重点实验室西安710049 西安热工研究院有限公司西安710054

二氧化硅气凝胶广泛用于各种航天器、飞行器的热防护中,添加遮光剂或纤维能大大改善其在高温下的隔热性能.本文通过计算辐射特性得到遮光剂和纤维不同温度下的最佳掺杂粒径,在复合材料等效热导率最小时得到最佳掺杂量,并应用优化结果设... 详细信息

二氧化硅气凝胶广泛用于各种航天器、飞行器的热防护中,添加遮光剂或纤维能大大改善其在高温下的隔热性能.本文通过计算辐射特性得到遮光剂和纤维不同温度下的最佳掺杂粒径,在复合材料等效热导率最小时得到最佳掺杂量,并应用优化结果设计了具有温度梯度的多层掺杂方案.研究发现:遮光颗粒和纤维的最佳掺杂直径随温度增加而减小,掺杂量随温度增加而增加,研究的4种遮光剂(碳黑、SiC、ZrO_2和TiO_2)中,碳黑具有最好遮光效果,但高温下会被氧化,SiC在高温下具有较好的遮光效果;石英纤维多层掺杂具有最小有效热导率,碳黑与SiC遮光剂和石英纤维共同掺杂对辐射传热的抑制最强.气凝胶复合材料背温实验结果有效证实了掺杂优化方法的正确性.

关键词：气凝胶遮光剂纤维最佳掺杂粒径最佳掺杂量多层掺杂